PURPOSE To assess differential patterns of axonal loss and demyelination in the optic nerve in multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). DESIGN Cross-sectional study. PARTICIPANTS One hundred ninety-two participants, including 136 MS patients (272 eyes), 19 NMOSD patients (38 eyes), and 37 healthy control participants (74 eyes). METHODS All participants underwent spectral-domain OCT scans and multifocal visual evoked potential (mfVEP) recordings. High-resolution magnetic resonance imaging (MRI) with the diffusion protocol also was performed in all patients. MAIN OUTCOME MEASURES Ganglion cell-inner plexiform layer (GCIPL) thickness and mfVEP amplitude and latency at 5 eccentricities; global and temporal retinal nerve fiber layer thickness. RESULTS In optic neuritis (ON) eyes, the NMOSD patients had more severe GCIPL loss (P < 0.001) and mfVEP amplitude reduction (P < 0.001) compared with MS patients, whereas in contrast, mfVEP latency delay was more evident in MS patients (P < 0.001). The NMOSD patients showed more morphologic and functional loss at the foveal to parafoveal region, whereas the MS patients showed evenly distributed damage at the macula. Correlation analysis demonstrated a strong structure-function (OCT-mfVEP) association in the NMOSD patients, which was only moderate in the MS patients. In non-ON (NON) eyes, the MS patients showed significantly thinner GCIPL than controls (P < 0.001), whereas no GCIPL loss was observed in NON eyes in NMOSD. In addition, a significant correlation was found between all OCT and mfVEP measures in MS patients, but not in NMOSD patients. MRI demonstrated significant lesional load in the optic radiation in MS compared to NMOSD eyes (P = 0.002), which was related to the above OCT and mfVEP changes in NON eyes. CONCLUSIONS Our study demonstrated different patterns of ON damage in NMOSD and MS. In MS, the ON damage was less severe, with demyelination as the main pathologic component, whereas in NMOSD, axonal loss was more severe compared with myelin loss. The disproportional mfVEP amplitude and latency changes suggested predominant axonal damage within the anterior visual pathway as the main clinical feature of NMOSD, in contrast to MS, where demyelination spreads along the entire visual pathway.

中文翻译：

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在多发性硬化症和神经脊髓炎性视神经频谱疾病中视神经损伤的结构和功能模式不同。

目的评估多发性硬化症（MS）和视神经脊髓炎光谱疾病（NMOSD）中视神经轴突丢失和脱髓鞘的差异模式。设计横断面研究。参与者192名参与者，包括136名MS患者（272眼），19名NMOSD患者（38眼）和37名健康对照参与者（74眼）。方法所有参与者均进行了光谱域OCT扫描和多焦点视觉诱发电位（mfVEP）记录。还对所有患者进行了具有扩散方案的高分辨率磁共振成像（MRI）。主要观察指标神经节细胞内丛状层（GCIPL）的厚度，mfVEP振幅和5个离心率时的潜伏期。全局和颞侧视网膜神经纤维层厚度。结果在视神经炎（ON）眼中，与MS患者相比，NMOSD患者的GCIPL丢失更为严重（P <0.001），mfVEP振幅降低（P <0.001），而相比之下，MS患者的mfVEP潜伏期延迟更为明显（P <0.001）。NMOSD患者在中央凹到中央凹区域表现出更多的形态和功能丧失，而MS患者在黄斑处分布均匀。相关性分析表明，NMOSD患者具有很强的结构功能（OCT-mfVEP）关联，而在MS患者中只有中等水平。在非ON（NON）眼中，MS患者的GCIPL显着小于对照组（P <0.001），而在NMOSD的NON眼中未观察到GCIPL的损失。此外，在MS患者的所有OCT和mfVEP测量之间发现了显着相关性，而在NMOSD患者中则没有。MRI显示，与NMOSD眼睛相比，MS的视线辐射具有明显的病变负荷（P = 0.002），这与上述OCT和NON眼睛中的mfVEP变化有关。结论我们的研究证明了NMOSD和MS中ON损伤的不同模式。在MS中，以脱髓鞘为主要病理成分，ON损伤较轻，而在NMOSD中，与髓鞘丢失相比，轴突丢失更为严重。mfVEP振幅和潜伏期的不成比例表明，前视路内的轴突损伤是NMOSD的主要临床特征，而MS则在整个视路中脱髓鞘扩散。结论我们的研究证明了NMOSD和MS中ON损伤的不同模式。在MS中，以脱髓鞘为主要病理成分，ON损伤较轻，而在NMOSD中，与髓鞘丢失相比，轴突丢失更为严重。mfVEP振幅和潜伏期的不成比例表明，前视路内的轴突损伤是NMOSD的主要临床特征，而MS则在整个视路中脱髓鞘扩散。结论我们的研究证明了NMOSD和MS中ON损伤的不同模式。在MS中，以脱髓鞘为主要病理成分，ON损伤较轻，而在NMOSD中，与髓鞘丢失相比，轴突丢失更为严重。mfVEP振幅和潜伏期的不成比例表明，前视路内的轴突损伤是NMOSD的主要临床特征，而MS则在整个视路中脱髓鞘扩散。